Geometric phases and hidden symmetries in simple resonators
H. Lauber, P. Weidenhammer, D. Dubbers
Geometric phases of real wave functions in nonintegrable quantum billiards are measured using microwave resonators. They appear as a sign change of the wave function after a cyclic excursion around a diabolic point in the space of shapes of the resonator. For a path encircling a pointlike triple degeneracy of an integrable system, an unexpected sign change for two out of the three wave functions is found, which must be attributed to a hidden symmetry, and not to a Berry phase.
Physical Review Letters•Feb 14, 1994•57 citations